At least one person was hurt when the parking garage at the Watergate complex suddenly collapsed.
A search was underway Friday evening to see if there are additional victims.
During the search, a dog received a positive hit inside the garage, according to D.C. Mayor Muriel Bowser. Officials said they do not know for sure if anyone is down there.
The parking garage, which was under construction, collapsed just after 10 a.m. Cars were crushed, concrete collapsed and everyone was evacuated.
"It looked like a war zone or something. It was nothing I've ever seen before in my life!" said Tom Wall, who went down to the garage to check on a friend's car. "His car was right next to the other car that got completely obliterated by building debris."
D.C. Fire and EMS said one person suffered minor injuries. Now, a cause is under investigation.
The 50-year-old Watergate is getting a $125 million facelift. Tenants said they've felt odd rumblings before. "Well there's a great deal of construction going on, so we hear things all day long," one man said.
Mayor Bowser said officials need to determine that the Watergate is safe before it can be reoccupied. Crews were working to shore up the structure.
Virginia Avenue was closed in the area as a result of the emergency activity.